1. Field of the Invention
The present invention relates to high performance automotive drag racing automatic transmissions and more particularly, to an improved tail housing for such automatic transmissions.
2. Description of the Related Art
Front engined automobiles generally utilize a drive shaft for coupling the transmission to the differential. The drive shaft generally includes a universal joint at each end to compensate for misalignment between the transmission output shaft and the differential input shaft. However, some types of drag racers are mid-engined, i.e., the engine is positioned behind the driver but ahead of the differential. This positioning of the heavy engine/transmission is to achieve a desired weight distribution in the vehicle for improved traction and handling. However, if the engine/transmission is positioned too close to the differential, there is insufficient room for a standard drive shaft and universal joints to compensate for misalignments between the transmission output shaft and the differential input shaft. Further, the engines in these drag racers generally produce great amounts of torque which, when coupled with the high traction of the drag racing tires, will cause the drag racing chassis to flex and twist during racing conditions, altering the alignment between the transmission output shaft and the differential input shaft. Uneven traction between the two driving tires will also cause the chassis to flex and twist. Thus, mere static alignment of the transmission output shaft and the differential input shaft is insufficient to maintain proper alignment during racing conditions.
In mid-engined drag racers employing automatic transmissions, a coupler assembly is used to mate the output shaft of the automatic transmission to the input shaft of the differential. The coupler assembly includes an internally splined male portion for engaging the splined output shaft of the transmission and an internally splined female portion for engaging the splined differential input shaft. The coupler assembly is relatively short and a forward portion of the coupler assembly is rotatably supported on its outer diameter by a standard bushing in the tail housing of the transmission. Because of the coupler assembly's short length and lack of universal joints, small misalignments between the transmission output shaft and the differential input shaft due to differential rotation and chassis flex and twist, will result in high loads being transmitted to the tail housing support bushing. This results in binding and increased bushing and seal failure as well as increased elapsed times and decreased top speed due to increased friction.